Idiot\'s Guides Basic Math and Pre-Algebra

Chapter 11: Coordinate Graphing 135

DEFINITION

The Cartesian coordinate system, named for René Descartes, is a rectangular

coordinate system that locates every point in the plane with an ordered pair

of numbers, (x,y). The x-coordinate indicates horizontal movement, and the

y-coordinate vertical movement.

The x-axis and y-axis divide the graphing area into four sections called quadrants. The following
graph shows the point (3,7) in the upper right quadrant, which is quadrant I. The point (-2,5) is in
the upper left quadrant, quadrant II. In the lower left quadrant, called quadrant III, you can see
the point (-3,-1), and in quadrant IV on the lower right, the point (4,-3). The point (5,0) sits on the
x-axis, and (0, 4) is on the y-axis.

-6 -2 062

-2

2

4

6

-4

-6

-8-9 -7 -5 -4 -1-3 134 5 78 9

-8

-9

-1

-3

-5

-7

8

9

1

3

5

7

-10 10

-10

10

y

x

Quadrant II Quadrant I

Quadrant III Quadrant IV

(3,7)

(-2,5)

(5,0)

(4,-3)

(-3,-1)

(0,4)